
// iterator_find_test

// pub trait Iterator {
//     // The type being iterated over.
//     type Item;

//     // `find` takes `&mut self` meaning the caller may be borrowed
//     // and modified, but not consumed.
//     fn find<P>(&mut self, predicate: P) -> Option<Self::Item> where
//         // `FnMut` meaning any captured variable may at most be
//         // modified, not consumed. `&Self::Item` states it takes
//         // arguments to the closure by reference.
//         P: FnMut(&Self::Item) -> bool {}
// }

pub fn iterator_find_test() {
    let vec1 = vec![1, 2, 3];
    let vec2 = vec![4, 5, 6];

    // `iter()` for vecs yields `&i32`.
    let mut iter = vec1.iter();
    // `into_iter()` for vecs yields `i32`.
    let mut into_iter = vec2.into_iter();

    // A reference to what is yielded is `&&i32`. Destructure to `i32`.
    println!("Find 2 in vec1: {:?}", iter     .find(|&&x| x == 2));
    // A reference to what is yielded is `&i32`. Destructure to `i32`.
    println!("Find 2 in vec2: {:?}", into_iter.find(| &x| x == 2));

    let array1 = [1, 2, 3];
    let array2 = [4, 5, 6];

    // `iter()` for arrays yields `&i32`
    println!("Find 2 in array1: {:?}", array1.iter()     .find(|&&x| x == 2));
    // `into_iter()` for arrays unusually yields `&i32`
    println!("Find 2 in array2: {:?}", array2.into_iter().find(|&&x| x == 2));
}